Using a metamaterial consisting of metals with subwavelength surface patterning, one can mimic surface plasmon polaritons(SPPs) and achieve surface waves with subwavelength confinement at microwave and terahertz frequ...Using a metamaterial consisting of metals with subwavelength surface patterning, one can mimic surface plasmon polaritons(SPPs) and achieve surface waves with subwavelength confinement at microwave and terahertz frequencies, thus bringing most of the advantages associated with the optical SPPs to lower frequencies. Due to the properties of strong field confinement and high local field intensity, spoof SPPs have demonstrated the improved performance for data transmission and device miniaturization in an intensively integrated environment. The distinctive abilities, such as suppression of transmission loss and bending loss, and increase of signal integrity, make spoof SPPs a promising candidate for future generation of electronic circuits and electromagnetic systems. This article reviews the progress in spoof SPPs with a special focus on their applications in circuits from transmission lines to passive and active devices in microwave and terahertz regimes. The integration of versatile spoof SPP devices on a single platform,which is compatible with established electronic circuits, is also discussed.展开更多
Wireless imaging,equippedwith ultralow power wireless communications and energy harvesting(EH)capabilities,have emerged as battery-free and sustainable solutions.However,the challenge of implementing wireless colour i...Wireless imaging,equippedwith ultralow power wireless communications and energy harvesting(EH)capabilities,have emerged as battery-free and sustainable solutions.However,the challenge of implementing wireless colour imaging in wearable applications remains,primarily due to high power demands and the need to balance energy harvesting efficiency with device compactness.To address these issues,we propose a flexible and wearable battery-free backscatter wireless communication system specially designed for colour imaging.The system features a hybrid RF-solar EH array that efficiently harvests energy from both ambient RF and visible light energy,ensuring continuous operation in diverse environments.Moreover,flexible materials allow the working system to conform to the human body,ensuring comfort,user-friendliness,and safety.Furthermore,a compact design utilizing a shared-aperture antenna array for simultaneous wireless information and power transfer(SWIPT),coupled with an optically transparent stacked structure.This design not only optimizes space but also maintains the performance of both communication and EH processes.The proposed flexible and wearable systems for colour imaging would have potentially applications in environmental monitoring,object detection,and law enforcement recording.This approach demonstrates a sustainable and practical solution for the next generation of wearable,power-demanding devices.展开更多
The terahertz region is a special region of the electromagnetic spectrum that incorporates the advantages of both microwaves and infrared light waves.In the past decade,metamaterials with effective medium parameters o...The terahertz region is a special region of the electromagnetic spectrum that incorporates the advantages of both microwaves and infrared light waves.In the past decade,metamaterials with effective medium parameters or gradient phases have been studied to control terahertz waves and realize functional devices.Here,we present a new approach to manipulate terahertz waves by using coding metasurfaces that are composed of digital coding elements.We propose a general coding unit based on a Minkowski closed-loop particle that is capable of generating 1-bit coding(with two phase states of 0 and 180°),2-bit coding(with four phase states of 0,90°,180°,and 270°),and multi-bit coding elements in the terahertz frequencies by using different geometric scales.We show that multi-bit coding metasurfaces have strong abilities to control terahertz waves by designing-specific coding sequences.As an application,we demonstrate a new scattering strategy of terahertz waves—broadband and wide-angle diffusion—using a 2-bit coding metasurface with a special coding design and verify it by both numerical simulations and experiments.The presented method opens a new route to reducing the scattering of terahertz waves.展开更多
Because of their exceptional capability to tailor the effective medium parameters,metamaterials have been widely used to control electromagnetic waves,which has led to the observation of many interesting phenomena,for...Because of their exceptional capability to tailor the effective medium parameters,metamaterials have been widely used to control electromagnetic waves,which has led to the observation of many interesting phenomena,for example,negative refraction,invisibility cloaking,and anomalous reflections and transmissions.However,the studies of metamaterials or metasurfaces are mainly limited to their physical features;currently,there is a lack of viewpoints on metamaterials and metasurfaces from the information perspective.Here we propose to measure the information of a coding metasurface using Shannon entropy.We establish an analytical connection between the coding pattern of an arbitrary coding metasurface and its far-field pattern.We introduce geometrical entropy to describe the information of the coding pattern(or coding sequence)and physical entropy to describe the information of the far-field pattern of the metasurface.The coding metasurface is demonstrated to enhance the information in transmitting messages,and the amount of enhanced information can be manipulated by designing the coding pattern with different information entropies.The proposed concepts and entropy control method will be helpful in new information systems(for example,communication,radar and imaging)that are based on the coding metasurfaces.展开更多
Metamaterials and metasurfaces have attracted much attention due to their powerful ability to control electromagnetic(EM)waves.In this paper,we review the recent developments in the field of EM metamaterials,starting ...Metamaterials and metasurfaces have attracted much attention due to their powerful ability to control electromagnetic(EM)waves.In this paper,we review the recent developments in the field of EM metamaterials,starting from their exotic physics to their applications in novel information systems.First,we show the fundamental understanding on traditional metamaterials based on the effective medium theory and related applications,such as invisibility cloaks and meta-lenses.Second,we review the two-dimensional versions of metamaterials,i.e.,metasurfaces,for controlling spatial waves and surface waves and thereafter present their typical designs.In particular,we briefly introduce spoof surface plasmon polaritons and their applications in microwave frequencies.Following the above approach,we emphatically present the concepts of digital coding metamaterials,programmable metamaterials,and information metamaterials.By extending the principles of information science to metamaterial designs,several functional devices and information systems are presented,which enable digital and EM-wave manipulations simultaneously.Finally,we give a brief summary of the development prospects for microwave metamaterials.展开更多
We demonstrate that asymmetric acoustic wave transmission in a waveguide can be achieved via gradient index metamaterials(GIMs). We theoretically prove that the acoustic wave can be efficiently converted to surface wa...We demonstrate that asymmetric acoustic wave transmission in a waveguide can be achieved via gradient index metamaterials(GIMs). We theoretically prove that the acoustic wave can be efficiently converted to surface waves(SWs) via GIMs. The GIMs in a waveguide can allow the transmission of acoustic waves in one direction but block them in the other direction. This theory is validated by experiments. Our findings may provide new applications in various scenarios such as high-efficiency acoustic couplers and noise control.展开更多
Programmable metasurface enables controlling electromagnetic (EM) waves in real time. By programming the states of active device embedded in metasurface element, the EM properties of the digital metasurface can be cha...Programmable metasurface enables controlling electromagnetic (EM) waves in real time. By programming the states of active device embedded in metasurface element, the EM properties of the digital metasurface can be changed quickly without redesigning their structures. However, large numbers of long-distance wires are required to connect the programmable metasurface to provide the coded signals from field programmable gate array (FPGA) when controlling the metasurface at a long distance, which is complicated and inconvenient. Here, we propose an infrared-controlled programmable metasurface that can be programmed remotely. The infrared transceiver is able to switch the coding sequences stored in the FPGA controller, thus controlling the voltage on the varactors integrated in the metasurface. Experiment is performed at microwave frequencies, and the measured results verify that the scattering beams of the metasurface sample can be changed remotely by using infrared ray. The proposed infrared-controlled programmable metasurface opens up avenues for constructing a new class of remotely-tuning dynamic metasurfaces.展开更多
基金supported in part from the National Natural Science Foundation of China(61871127,61735010,61631007,61571117,61501112,61501117,61522106,61722106,61701107,61701246 and 61701108)the Fundamental Research Funds for the Central Universities(2242018R30001)+1 种基金National Key Research and Development Program of China(2017YFA0700201,2017YFA0700202,and 2017YFA0700203)the 111 Project(111-2-05)
文摘Using a metamaterial consisting of metals with subwavelength surface patterning, one can mimic surface plasmon polaritons(SPPs) and achieve surface waves with subwavelength confinement at microwave and terahertz frequencies, thus bringing most of the advantages associated with the optical SPPs to lower frequencies. Due to the properties of strong field confinement and high local field intensity, spoof SPPs have demonstrated the improved performance for data transmission and device miniaturization in an intensively integrated environment. The distinctive abilities, such as suppression of transmission loss and bending loss, and increase of signal integrity, make spoof SPPs a promising candidate for future generation of electronic circuits and electromagnetic systems. This article reviews the progress in spoof SPPs with a special focus on their applications in circuits from transmission lines to passive and active devices in microwave and terahertz regimes. The integration of versatile spoof SPP devices on a single platform,which is compatible with established electronic circuits, is also discussed.
基金supported by the National Science Funds for Distinguished Young Scientists under grant number 61925103the Project for Jiangsu Specially Appointed Professor,National Natural Science Foundation of China(NSFC)62101115the Fundamental Research Funds for the Central Universities 2242022k60004.
文摘Wireless imaging,equippedwith ultralow power wireless communications and energy harvesting(EH)capabilities,have emerged as battery-free and sustainable solutions.However,the challenge of implementing wireless colour imaging in wearable applications remains,primarily due to high power demands and the need to balance energy harvesting efficiency with device compactness.To address these issues,we propose a flexible and wearable battery-free backscatter wireless communication system specially designed for colour imaging.The system features a hybrid RF-solar EH array that efficiently harvests energy from both ambient RF and visible light energy,ensuring continuous operation in diverse environments.Moreover,flexible materials allow the working system to conform to the human body,ensuring comfort,user-friendliness,and safety.Furthermore,a compact design utilizing a shared-aperture antenna array for simultaneous wireless information and power transfer(SWIPT),coupled with an optically transparent stacked structure.This design not only optimizes space but also maintains the performance of both communication and EH processes.The proposed flexible and wearable systems for colour imaging would have potentially applications in environmental monitoring,object detection,and law enforcement recording.This approach demonstrates a sustainable and practical solution for the next generation of wearable,power-demanding devices.
基金This work was supported by the National High Tech Projects(2012AA030402 and 2011AA010202)the National Science Foundation of China(61138001,61171024,61171026,61371035 and 11227904)+2 种基金the 111 Project(111-2-05)the Natural Science Foundation of Jiangsu Province(BK2012019)and the 973 Program(2014CB339800).
文摘The terahertz region is a special region of the electromagnetic spectrum that incorporates the advantages of both microwaves and infrared light waves.In the past decade,metamaterials with effective medium parameters or gradient phases have been studied to control terahertz waves and realize functional devices.Here,we present a new approach to manipulate terahertz waves by using coding metasurfaces that are composed of digital coding elements.We propose a general coding unit based on a Minkowski closed-loop particle that is capable of generating 1-bit coding(with two phase states of 0 and 180°),2-bit coding(with four phase states of 0,90°,180°,and 270°),and multi-bit coding elements in the terahertz frequencies by using different geometric scales.We show that multi-bit coding metasurfaces have strong abilities to control terahertz waves by designing-specific coding sequences.As an application,we demonstrate a new scattering strategy of terahertz waves—broadband and wide-angle diffusion—using a 2-bit coding metasurface with a special coding design and verify it by both numerical simulations and experiments.The presented method opens a new route to reducing the scattering of terahertz waves.
基金supported in part by the National Science Foundation of China(Grant Nos.61171024,61171026,61302018,61401089,61571117,61501112,61501117 and 61631007)the 111 Project(Grant No.111-2-05)the National Instrumentation Program(Grant No.2013YQ200647).
文摘Because of their exceptional capability to tailor the effective medium parameters,metamaterials have been widely used to control electromagnetic waves,which has led to the observation of many interesting phenomena,for example,negative refraction,invisibility cloaking,and anomalous reflections and transmissions.However,the studies of metamaterials or metasurfaces are mainly limited to their physical features;currently,there is a lack of viewpoints on metamaterials and metasurfaces from the information perspective.Here we propose to measure the information of a coding metasurface using Shannon entropy.We establish an analytical connection between the coding pattern of an arbitrary coding metasurface and its far-field pattern.We introduce geometrical entropy to describe the information of the coding pattern(or coding sequence)and physical entropy to describe the information of the far-field pattern of the metasurface.The coding metasurface is demonstrated to enhance the information in transmitting messages,and the amount of enhanced information can be manipulated by designing the coding pattern with different information entropies.The proposed concepts and entropy control method will be helpful in new information systems(for example,communication,radar and imaging)that are based on the coding metasurfaces.
基金supported by the National Key Research and Development Program of China(Nos.2017YFA0700201,2017YFA0700202,and 2017YFA0700203)the National Natural Science Foundation of China(Nos.61631007,61731010,61735010,61722106,61701107,and 61701108)+3 种基金the Fund for International Cooperation and Exchange of the National Natural Science Foundation of China(No.61761136007)the 111 Project(No.111-2-05)the Fundamental Research Funds for the Central Universities,the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(No.KYCX17_0092)the Scientific Research Foundation of Graduate School of Southeast University,China(No.YBJJ-1815)。
文摘Metamaterials and metasurfaces have attracted much attention due to their powerful ability to control electromagnetic(EM)waves.In this paper,we review the recent developments in the field of EM metamaterials,starting from their exotic physics to their applications in novel information systems.First,we show the fundamental understanding on traditional metamaterials based on the effective medium theory and related applications,such as invisibility cloaks and meta-lenses.Second,we review the two-dimensional versions of metamaterials,i.e.,metasurfaces,for controlling spatial waves and surface waves and thereafter present their typical designs.In particular,we briefly introduce spoof surface plasmon polaritons and their applications in microwave frequencies.Following the above approach,we emphatically present the concepts of digital coding metamaterials,programmable metamaterials,and information metamaterials.By extending the principles of information science to metamaterial designs,several functional devices and information systems are presented,which enable digital and EM-wave manipulations simultaneously.Finally,we give a brief summary of the development prospects for microwave metamaterials.
基金supported by the National Key Research and Development Program of China(2017YFA0700201,2017YFA0700202,and 2017YFA0700203)the National Natural Science Foundation of China(61631007,61571117,61138001,61371035,61722106,61731010 and 11227904)the 111Project(111-2-05)
文摘We demonstrate that asymmetric acoustic wave transmission in a waveguide can be achieved via gradient index metamaterials(GIMs). We theoretically prove that the acoustic wave can be efficiently converted to surface waves(SWs) via GIMs. The GIMs in a waveguide can allow the transmission of acoustic waves in one direction but block them in the other direction. This theory is validated by experiments. Our findings may provide new applications in various scenarios such as high-efficiency acoustic couplers and noise control.
基金This work was supported by the National Key Research and Development Program of China(2017YFA0700201,2017YFA0700203 and 2016YFC0800401)National Natural Science Foundation of China(61890544,61522106,61631007,61571117,61731010,61735010,61722106,61701107,and 61701108)+3 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX19_0081)Scientific Research Foundation of Graduate School of Southeast University(YBPY1938)Foundation of National Excellent Doctoral Dissertation of China(201444)the 111 Project(111-2-05).
文摘Programmable metasurface enables controlling electromagnetic (EM) waves in real time. By programming the states of active device embedded in metasurface element, the EM properties of the digital metasurface can be changed quickly without redesigning their structures. However, large numbers of long-distance wires are required to connect the programmable metasurface to provide the coded signals from field programmable gate array (FPGA) when controlling the metasurface at a long distance, which is complicated and inconvenient. Here, we propose an infrared-controlled programmable metasurface that can be programmed remotely. The infrared transceiver is able to switch the coding sequences stored in the FPGA controller, thus controlling the voltage on the varactors integrated in the metasurface. Experiment is performed at microwave frequencies, and the measured results verify that the scattering beams of the metasurface sample can be changed remotely by using infrared ray. The proposed infrared-controlled programmable metasurface opens up avenues for constructing a new class of remotely-tuning dynamic metasurfaces.
